We have developed computer programs for the simulation of plasma insulin and glucose dynamics after subcutaneous injection of insulin. The program incorporates a pharmacokinetic model to calculate the time courses of plasma insulin for various combinations of popular preparations (Regular, NPH, Lente, Ultralente). Utilizing a pharmacodynamic model describing the dependence of glucose dynamics on plasma insulin and glucose levels, the program can predict the expected time course of plasma glucose in response to a change in carbohydrate intake, insulin dosage, timing or regimen. A set of typical parameters has been obtained by analysis of data from the literature. Several computer simulations have been generated to evaluate the effects on insulin and glucose profiles of systematically changing insulin regimen, dose, timing of meals or timing of preprandial insulin administration. The program can be used to explore on a theoretical basis the impact of various factors associated with glycemic control. As an educational tool the program provides a suitable environment for demonstration of the combined or isolated effects of insulin and diet on glycemia. Further, we have developed programs for analysis of blood glucose values obtained by persons performing self-monitoring of blood glucose. These programs provide several novel features, including an animated computer "movie" showing how the 24 hour glucose profile changes longitudinally with time. For a patient with a stable pattern of intake, exercise and endogenous (hepatic) glucose production, one can predict the "ideal insulin profile." We use a simplified, linearized model, to permit one to optimize the doses of insulin for any one of eight insulin regimens (involving up to four injections per day), to most closely approximate this ideal insulin profile, and to select the best regimen. This program (Glucoject, Version 2) should be useful for teaching purposes and for decision support. Another version, CADMO, provides an English language interpretation of the GLUCOJECT output, to facilitate use by paramedical personnel and physicians. Preliminary results also indicate the potential utility of electronic exercise monitors to automatically capture data regarding constancy of patient lifestyle, to help in the interpretation of data from the glucose memory meters.